CN113840960A

CN113840960A - Pulp mixture

Info

Publication number: CN113840960A
Application number: CN201980088173.4A
Authority: CN
Inventors: I·B·巴顿; T·博尔顿; D·J·尼科尔森; S·T·施内勒
Original assignee: Hercules LLC
Current assignee: Hercules LLC
Priority date: 2018-11-30
Filing date: 2019-11-22
Publication date: 2021-12-24
Anticipated expiration: 2039-11-22
Also published as: BR112021010531A2; CL2021001415A1; EP3887599A4; US10941524B2; KR20210096636A; CN113840960B; WO2020112518A1; US20200173111A1; CA3121485A1; EP3887599B1; EP3887599A1

Abstract

The pulp mixture comprises lignocellulosic material, water, lignin, inorganic salts, and a copolymer comprising two or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof. The copolymer is free of silicone-containing structural units and lignin is present in an amount greater than about 150ppm based on the total weight of the pulp mixture.

Description

Pulp mixture

Cross Reference to Related Applications

This application claims the benefit of U.S. application No. 16/205,798 filed on 30/11/2018.

Technical Field

The present disclosure generally relates to pulp mixtures that generally exhibit improved drainage during pulp washing. More specifically, the present disclosure relates to a pulp mixture comprising a specific copolymer free of silicone-containing structural units.

Background

Washing at various points in the pulp production process can be a bottleneck. Increasing the washing speed can alleviate this bottleneck. Alternatively, the production speed may be kept constant and the pulp may be washed more thoroughly. This alternative method saves chemicals that are normally recovered in the wash effluent and may also lead to chemical savings in subsequent stages of processing cleaner pulp.

The washing efficiency is especially important before and during bleaching of the pulp. Improving the washing efficiency saves bleaching chemicals, which is one of the largest costs in pulp mills. Some of the effluent from treating the pulp (e.g. after contacting the pulp with chlorine-containing chemicals) must also be treated by an on-site wastewater treatment plant before discharge. Minimizing water and chemical usage during bleaching is an important industry need.

Generally, the chemical treatment of pulp during and between bleaching stages is limited to the types of products that can be used due to pulp quality issues. This is particularly important for specialty pulps that are highly regulated or require a particular level of cleanliness. Examples of such specialty pulps include fluff pulp, pulp for cellulose derivative manufacture and dissolving pulp. However, even large commercial pulp producers limit the types of products that can be used. For example, many products limit the use of silicone-based defoamers and drainage enhancing compounds.

Thus, there remains an opportunity to develop compounds useful in pulp production that have properties similar to or superior to existing silicone-based products. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description of the disclosure and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.

Disclosure of Invention

The present disclosure provides a pulp mixture comprising a lignocellulosic material, water, lignin, an inorganic salt, and a copolymer comprising two or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof. The copolymer is free of silicone-containing structural units and lignin is present in an amount greater than about 150ppm based on the total weight of the pulp mixture.

The present disclosure also provides a method for improving drainage during pulp washing. The method includes providing the above pulp mixture, forming a pulp mat from the pulp mixture, and filtering water from the pulp mat. In this embodiment, the pulp mixture exhibits at least about a 5% increase in drainage rate from the pulp mat in the presence of the copolymer as compared to the drainage rate from the pulp mat in the absence of the copolymer.

Drawings

The invention will now be described with reference to the following figures, in which

FIG. 1 is a bar graph of the increase in drainage rate as a function of copolymer selection, as described in example 1;

FIG. 2 is a second bar graph of water drainage rate increase as a function of copolymer selection, also as described in example 1;

FIG. 3 is a bar graph of the increase in drainage rate as a function of copolymer selection, as described in example 2;

FIG. 4 is a table of the filtrate volumes and copolymers collected per unit time, as described in example 3;

fig. 5 is a line graph of the collected filtrate volume as a function of time after the start of drainage, as described in example 3;

FIG. 6 is a bar graph of the increase in drainage rate as a function of copolymer selection, as described in example 4;

FIG. 7 is a second bar graph of water drainage rate increase as a function of copolymer selection, also as described in example 4;

FIG. 8 is a bar graph of the increase in drainage rate as a function of copolymer selection, as described in example 5;

FIG. 9 is a bar graph of the calculated Chemical Oxidant Demand (COD) percentage in the filtrate removed from the pulp and the calculated Total Organic Carbon (TOC) percentage in the filtrate removed from the pulp as a function of copolymer selection, also as described in example 5;

FIG. 10 is a bar graph of the increase in drainage rate as a function of copolymer selection, as described in example 6; and is

FIG. 11 is a bar graph of the removed filtrate as a function of copolymer selection, as described in example 7.

Detailed Description

The following detailed description is merely exemplary in nature and is not intended to limit the pulp mixture or process of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Embodiments of the present disclosure generally relate to pulp mixtures and methods of forming and using the same. For the sake of brevity, conventional techniques related to pulp mixtures may not be described in detail herein. Further, various tasks and process steps described herein may be incorporated into a more comprehensive operation or process having additional steps or functions not described in detail herein. In particular, the various steps of forming a pulp mixture are well known, and thus, for the sake of brevity, many conventional steps will only be mentioned briefly herein or will be omitted entirely without providing well known process details.

The present disclosure provides a pulp mixture. The pulp mixture comprises lignocellulosic material, water, lignin, inorganic salts, and a copolymer comprising two or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof. In various embodiments, the pulp mixture consists essentially of lignocellulosic material, water, lignin, inorganic salts, and copolymers. The pulp mixture may be free of any one or more additional polymers, including but not limited to silicone polymers.

In various embodiments, the pulp mixture exhibits an increase in drainage rate in the presence of the copolymer as compared to a pulp mixture drained in the absence of the copolymer. For example, the pulp blend may exhibit at least about a 5%, about a 10%, about a 15%, about a 20%, about a 25%, about a 30%, about a 35%, about a 40%, about a 45%, about a 50%, about a 55%, about a 60%, about a 65%, about a 70%, about a 75%, etc. increase in drainage rate from the pulp mat in the presence of the copolymer as compared to drainage rate from the pulp mat in the absence of the copolymer. For example, these rates may fluctuate when measured relative to brown stock drainage or bleached pulp extraction stage drainage.

In other embodiments, the pulp mixture exhibits an increase in dewatering rate, defined as the amount of water passing through the pulp mat per unit of wash time in the presence of the copolymer, of at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, etc., as compared to the amount of water passing through the pulp mat per unit of wash time in the absence of the copolymer.

In further embodiments, the pulp mixture comprising inorganic salts exhibits a reduction in the amount of inorganic salts of at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, etc., as compared to the drainage rate from the pulp mat in the absence of the copolymer, calculated on a mass balance basis and as measured by Total Dissolved Solids (TDS) after filtering water from the pulp mat in the presence of the copolymer.

Pulp mixture

The pulp mixture may alternatively be described as a pulp slurry. The pulp mixture comprises lignocellulosic material. The lignocellulosic material may be any material known in the art. Lignocellulosic material can be described as lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from a fiber source such as wood, paper, and the like. The lignocellulosic material may be, or may be based on, virgin pulp, deinked pulp (DIP), unbleached kraft pulp (UBK), mechanical pulp such as thermomechanical pulp (TMP), semichemical mechanical pulp such as neutral sulfite semichemical pulp (NSSC), Old Corrugated Containers (OCC), recycled newspapers, recycled paper towels, or other fiber sources. Typically, the lignocellulosic material is present in the pulp mixture in an amount of from about 0.5 to about 20 wt.%, from about 1 to about 19 wt.%, from about 2 to about 18 wt.%, from about 3 to about 17 wt.%, from about 4 to about 16 wt.%, from about 5 to about 15 wt.%, or from about 6 to about 14 wt.%, from about 7 to about 13 wt.%, from about 8 to about 12 wt.%, from about 9 to about 11 wt.%, or from about 10 to about 11 wt.%, based on the total weight of the pulp mixture. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

The pulp mixture may have any fiber consistency. In various embodiments, the fiber consistency is about 0.5%, 1%, or 2% or higher, such as about 2 to about 3%, about 3 to about 4%, about 2 to about 4%, or about 4%. Typically, the water is present in the pulp mixture in an amount of at least about 80, 85, 90, 95, etc. weight percent, based on the total weight of the pulp mixture. In other embodiments, the water is present at about 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or nearly 100 weight percent based on the total weight of the pulp mixture. In various embodiments, all values and ranges of values (including those described above and those between) are expressly contemplated herein.

The lignin itself is present in an amount greater than about 150ppm based on the total weight of the pulp mixture. In various embodiments, the lignin is present in an amount up to about 25,000, 50,000, 75,000, or 100,000ppm, based on the total weight of the pulp mixture. In other embodiments, the lignin is present in the pulp mixture in an amount of from about 200 to about 4000, from about 500 to about 3500, from about 1000 to about 3000, from about 1500 to about 2500, or from about 2000 to about 2500ppm, based on the total weight of the pulp mixture. In other embodiments, the amount of lignin is from about 200 to about 1000, from about 300 to about 900, from about 400 to about 800, from about 500 to about 700, or from about 600 to about 700ppm, based on the total weight of the pulp mixture. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

The inorganic salt is not particularly limited and may be any salt known in the art. For example, as understood by those skilled in the art, the inorganic salt may be NaOH, Na₂S、Na₂CO₃、Na₂SO₃、Na₂SO₄、 Na₂S₂O₃Etc., or combinations thereof. Approximately the highest concentration of inorganic salts is found in black liquor. In various embodiments, the concentrations of the various inorganic salts are: about 5 to about 10 weight percent NaOH, about 15 to about 25 weight percent Na₂S, about 35 to about 40 wt% Na₂CO₃About 5 to about 10% Na₂SO₃About 10 to about 15% Na₂SO₄And about 15 to about 20 wt.% Na₂S₂O₃Each based on the total weight of the pulp mixture. In various embodiments, one or more of these salts may be present in an amount of from about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. up to about 40 wt.%, based on the total weight of the pulp mixture. The total residual amount of these inorganic salts is generally less than 3% by weight. In various embodiments, all values and ranges of values (including those described above and those intermediate to those described above) are specifically contemplated herein.

The pulp mixture may also contain inorganic mineral and organic extracts such as fatty and resin acids, dissolved organic compounds (including cellulosic and hemicellulose sugars/oligomers), fatty and resin acid soaps, and combinations thereof. These compounds are also not particularly limited and may be any compounds known in the art. Further, they may be present in any typical amount known in the art. In various embodiments, the organic extract is present in an amount of about 1 to about 10 weight percent, based on the total weight of the pulp mixture. In various embodiments, the present disclosure is directed to the removal of fatty acids and their soap and resin acids.

A reduction in extractives and inorganic salts remaining in the pulp mixture after washing is an indication of increased cleanliness. These are considered contaminants in bleaching plants, resulting in increased bleaching costs, reduced productivity and even downtime for cleaning. The dirt in the paper can lead to poor paper quality. In addition, these contaminants can lead to equipment fouling. Cleaning can be achieved by increased dewatering and better washing.

The pulp mixture also includes a copolymer including one or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof. Ethylene oxide (E/O) and propylene oxide (P/O) units are known in the art.

The term "(meth) acrylic acid unit" describes both methacrylic acid units (i.e. acrylic acid units comprising a methyl group) and acrylic acid units not comprising a methyl group. In other words, the term "(methyl)" placed in parentheses indicates that methyl is optional and may or may not be included in the definition of acrylic units.

Furthermore, the copolymer contains no structural units containing silicone. In other words, the copolymer is not a silicone copolymer and does not contain any "Si" atoms or units. Furthermore, the pulp mixture itself may be free of any additional silicone polymer or copolymer not related to the above-described copolymer. Alternatively, the pulp mixture may be substantially free of silicone polymers or copolymers, for example, containing less than 5, 4, 3, 2, 1, 0.5, or 0.1 weight percent of silicone polymers or copolymers based on the total weight of the pulp mixture. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

Examples of silicone polymers or copolymers that are generally excluded include any one or more of those described in the examples below or the Momentive Silwet L7200 series, Wacker Pulpsil 900S series, and/or the Dow Corning 5000 series. Typical compounds are shown below. Further, in various embodiments, the pulp mixture is free of Rake, drape, and/or ABA type silicone copolymers.

Referring again to the copolymers of the present disclosure as such, the copolymers may comprise one or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, and combinations thereof. For example, the copolymer may be a linear copolymer and comprise ethylene oxide units and propylene oxide units. In one embodiment, the copolymer has a structure according to formula (I),

in this formula (I), x and y independently of each other have a value of about 1 to about 200. In various embodiments, x is independently from about 5 to about 40, about 5 to about 35, about 5 to about 30, about 10 to about 25, about 15 to about 20, 5, 10, 15, 20, 25, 30, 35, 40, and the like. In other embodiments, y is independently from about 5 to about 40, about 5 to about 35, about 5 to about 30, about 10 to about 25, about 15 to about 20, 5, 10, 15, 20, 25, 30, 35, 40, and the like. In other embodiments, the ratio of x: y is from about 10: 1 to about 1: 10, such as about 9: 1, about 8: 1, about 7: 1, about 6: 1, about 5: 1, about 4: 1, about 3: 1, about 2: 1, about 1: 2, about 1: 3, about 1: 4, about 1: 5, about 1: 6, about 1: 7, about 1: 8, or about 1: 9, or any range therebetween. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

In other embodiments, the copolymer is a branched copolymer and comprises ethylene oxide units and propylene oxide units. For example, the copolymer can have a core and two or more chains extending from the core (which form branches of the branched copolymer). The core itself may be any known in the art. For example, the core may be derived from a hydroxyl-containing compound, including but not limited to a hydroxyl-containing compound selected from the group consisting of sorbitan, glycerol, erythritol, and combinations thereof. In various embodiments, two or more chains independently comprise ethylene oxide units and/or propylene oxide units. In one embodiment, the copolymer has a structure according to formula (II),

in this formula (II), a, b, c, d, w, x, y and z each independently of one another have a value of from about 1 to about 200. In various embodiments, each of w, x, y, and z independently has a value of about 5 to about 50. In other embodiments, each of w, x, y, and z independently has a value of from about 10 to about 30. In further embodiments, each of w, x, y, and z independently has a value of about 12 to about 24. In still further embodiments, each of a, b, c, and d has a value of from about 7 to about 70. In other embodiments, each of a, b, c, and d has a value of from about 12 to about 40. In further embodiments, each of a, b, c, and d has a value of from about 14 to about 28. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

Further, the w: a ratio, the x: b ratio, the y: c ratio, and the z: d ratio are each independently from one another from about 10: 1 to about 1: 10. In various embodiments, one or more of these ratios are independently about 9: 1, about 8: 1, about 7: 1, about 6: 1, about 5: 1, about 4: 1, about 3: 1, about 2: 1, about 1: 2, about 1: 3, about 1: 4, about 1: 5, about 1: 6, about 1: 7, about 1: 8, or about 1: 9, or any range therebetween. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

In other embodiments, the copolymer comprises one or more structural units selected from the group consisting of (meth) acrylic acid units, ethyl acrylate units, and combinations thereof. As above, the term "(meth) acrylic acid unit" describes both methacrylic acid units (i.e. acrylic acid units comprising a methyl group) and acrylic acid units free of a methyl group. In other words, the term "(methyl)" placed in parentheses indicates that methyl is optional. In various embodiments, the copolymer is a random copolymer comprising the units described below with respect to the "x" and "y" subscripts. Alternatively, as will be understood by those skilled in the art, the copolymers may be described as block type copolymers.

In various embodiments, the copolymer has a structure according to formula (III),

in this formula (III), each of x and y independently of each other has a value of about 1 to about 200. In other embodiments, the value of each of x and y is independently any number or range of numbers between and including 1 and 200. Further, the ratio of x: y is from about 10: 1 to about 1: 10. In various embodiments, the ratio is about 9: 1, about 8: 1, about 7: 1, about 6: 1, about 5: 1, about 4: 1, about 3: 1, about 2: 1, about 1: 2, about 1: 3, about 1: 4, about 1: 5, about 1: 6, about 1: 7, about 1: 8, or about 1: 9, or any range therebetween. . In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

The copolymer is not particularly limited based on the amount contained in the pulp mixture. However, in one embodiment, the copolymer is present in an amount of from about 0.10 to about 3.0 pounds of active per U.S. ton of oven dried pulp. In other embodiments, the amount is from about 0.1 to about 1, about 0.1 to about 0.5, about 0.5 to about 1, or about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 pound of active per U.T. oven dried pulp. In various embodiments, all values and ranges of values (including and intermediate to those described above) are expressly contemplated herein.

In one embodiment, the lignocellulosic material is present in an amount of about 0.5 to about 20 weight percent based on the total weight of the pulp mixture, water is present in an amount of at least about 75 weight percent based on the total weight of the pulp mixture, the inorganic salt is present in the virgin black liquor in the brown stock discharged from the digester in an amount of about 6 weight percent based on the total weight of the pulp, is present in the washed black liquor in less than about 3 weight percent per mayton oven dried pulp, is present in the unwashed bleached raw pulp in less than about 3 weight percent per mayton oven dried pulp, and is present in the unwashed extraction stage bleached raw pulp in less than about 2 percent per mayton oven dried pulp.

Method for increasing drainage rate during pulp washing

The present disclosure also provides a method for increasing the drainage rate during pulp washing. The method includes the step of providing a pulp mixture. The providing step is not particularly limited and may alternatively be described as supplying or otherwise making available the pulp mixture and copolymer to the process.

The method further comprises the steps of forming a pulp mat from the pulp mixture and filtering water from the pulp mat. In this step, the pulp mat exhibits an increase in drainage rate in the presence of the copolymer as compared to a drained pulp mat in the absence of the copolymer as first introduced above. The water filtration step may be further defined as any water filtration step known in the art. In one embodiment, the draining step is performed in a brown stock washing process, a bleaching plant process, a commercial pulp machine process, or a combination thereof.

In various embodiments of the method, the pulp mixture exhibits an increase in drainage rate in the presence of the copolymer as compared to a pulp mixture drained in the absence of the copolymer. For example, the pulp mixture may exhibit at least about a 5%, about a 10%, about a 15%, about a 20%, about a 25%, about a 30%, about a 35%, about a 40%, about a 45%, about a 50%, about a 55%, about a 60%, about a 65%, about a 70%, about a 75%, etc. increase in drainage rate from the pulp mat in the presence of the copolymer as compared to drainage rate from the pulp mat in the absence of the copolymer. For example, these rates may fluctuate when measured relative to brown stock drainage or bleached pulp extraction stage drainage.

Method for increasing dehydration rate

The present disclosure also provides a method of increasing the rate of dehydration. The method includes the step of providing a pulp mixture. The providing step is not particularly limited and may alternatively be described as supplying or otherwise making available the pulp mixture and copolymer to the process.

The method further comprises the steps of forming a pulp mat from the pulp mixture and dewatering the pulp mat. In this step, the pulp mat exhibits an increased rate of dewatering of the pulp mat in the presence of the copolymer compared to the pulp mat dewatered in the absence of the copolymer first described above. In various embodiments, the pulp mixture exhibits an increase in dewatering rate, defined as the amount of water passing through the pulp mat per unit of wash time in the presence of the copolymer, of at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, etc., as compared to the amount of water passing through the pulp mat per unit of wash time in the absence of the copolymer.

Method for improved inorganic salt removal

The present disclosure also provides a method for improving the removal of inorganic salts from a pulp mixture. The method comprises the step of providing a pulp mixture. The providing step is not particularly limited and may alternatively be described as supplying or otherwise making available the pulp mixture and copolymer to the process.

The method further comprises the steps of forming a pulp mat from the pulp mixture and filtering water from the pulp mat. The draining step may be further defined as any draining step known in the art. In one embodiment, the draining step is performed in a brown stock washing process, a bleaching plant process, a commercial pulp machine process, or a combination thereof. In this method, the removal of inorganic salts is measured after filtration of water from the pulp mat in the presence of the copolymer, as compared to filtration of water from the pulp mat in the absence of the copolymer. In further embodiments, the pulp mixture comprising inorganic salts exhibits a reduction in the amount of inorganic salts, calculated on a mass balance basis and as measured by Total Dissolved Solids (TDS) after filtration of water from the pulp mat in the presence of the copolymer, of at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, etc., as compared to filtration of water from the pulp mat in the absence of the copolymer.

Examples

The examples set forth below investigate drainage performance using a custom designed apparatus that allows dirty pulp to be dewatered under controlled vacuum conditions at hot processing temperatures. The following sets forth an experimental protocol in which the output is a simple measure of the mass of effluent collected through the screen over the time interval measured. The time and mass of the collected effluent data can be plotted to show the drainage curve, or the mass collected at a particular time (e.g., 15 to 25 seconds) can be directly compared for different copolymers or comparative examples.

Example 1:

unbleached maple kraft brown stock at 3% solids was drained in a test apparatus along with unbleached southern oak and aspen wood blends. 125mL of black liquor effluent was drained after treatment with 4lb of each copolymer active per metric ton of OD pulp as described below. The treated pulp was compared to an untreated sample drained to remove the same amount of effluent.

More specifically, copolymers 1-3 were evaluated and identified as follows: each of the copolymers 1-3 is an EO/PO block copolymer having the following general formula according to the following formula (II):

with respect to copolymer 1, each w, x, y, z is about 6, and a, b, c, d is about 36.

With respect to copolymer 2, each x is about 20 and y is about 24.

With respect to copolymer 3, each x is about 10 and y is about 12.

The data shows that the treated samples were drained more quickly, thereby reducing the elapsed time to reach 125mL of collected effluent black liquor. The time savings translates to a% difference for comparison. The drainage rate is significantly improved by treatment of the copolymer. These results are presented in fig. 1 and 2, where fig. 1 includes data relating to an unbleached maple kraft brown stock at 3% solids content and fig. 2 includes data relating to an unbleached southern oak and aspen wood blend.

Example 2

Unbleached birch kraft brown stock was evaluated. Silicone-free compositions comprising various copolymers were tested against silicone-based antifoam containing silicone polyether Surfactant (SPE) filter aid and silicone-free products commercially available from BIM Kemi AB. These compounds were applied to 3% pulp at a dose of 500g/MT OD pulp before water filtration.

More specifically, the (co) polymers 4-8 were evaluated and identified as follows:

polymer 4 is a silicone emulsion defoamer containing a silicone polyether Surfactant (SPE) filter aid, commercially available from Solenis under the tradename advantaged BN 3397.

Copolymer 5 is a 2% active solution of copolymer 2 in water.

Copolymer 6 is a 10% active solution of copolymer 2 in water.

Copolymer 7 is a 10% active solution of copolymer 2 in water.

Polymer 8 is a silicone emulsion defoamer commercially available from BIM Kemi AB under the trade name AF 4442.

The data set forth in fig. 3 show a significant increase in drainage rate by the copolymer treatment compared to copolymer 8.

Example 3:

unbleached eucalyptus kraft brown stock was evaluated immediately prior to testing with the produced refiner. The 3% pulp was drained to 8-10% solids in the test apparatus to form a pad. Clean hot water was then displaced through the pad to simulate washing. Each copolymer was added at 1 pound of active per ton of OD pulp and evaluated at process temperature.

More specifically, (co) polymers 9-11 were evaluated and identified as follows:

polymer 9 is a silicone polyether surfactant commercially available from Momentive under the trade name Silwet DA-40.

Polymer 10 is a silicone polyether surfactant commercially available from Momentive under the trade name Silwet DA-33.

The copolymer 11 has the same characteristics as the above-mentioned copolymer 2.

The data in the table of fig. 4 and the line graph in fig. 5 show that the filtrate volume collected per unit time is significantly greater for the treated pulp. The data also show that the performance of the non-silicone EO/PO block copolymers of the present disclosure is similar to the best silicone polyether Surfactant (SPE) used in this example.

Example 4:

unbleached northern pine/hemlock mixed kraft brown stock is drained in a test apparatus along with pine/hemlock mixed kraft brown stock. 125mL of black liquor effluent was drained after treatment with 4lb of each copolymer active per metric ton OD pulp. The treated pulp was compared to an untreated sample drained to remove the same amount of effluent.

More specifically, copolymers 12-14 were evaluated and determined as follows:

the copolymer 12 has the same characteristics as the above-mentioned copolymer 1.

The copolymer 13 has the same characteristics as the above-mentioned copolymer 2.

The copolymer 14 has the same characteristics as the copolymer 3 described above.

The data shows that the treated samples were drained more quickly, thereby reducing the elapsed time to reach 125mL of collected effluent black liquor. The time savings were converted to% difference for comparison as shown in fig. 6 and 7, where fig. 6 includes data related to unbleached northern pine/hemlock blended kraft brown stock and fig. 7 includes data related to pine/fir blended kraft brown stock. Drainage rate is increased by treatment of the copolymers of the present disclosure.

Example 5:

bleached northern hardwood kraft pulp from the extraction stage wash was simulated with pulp and effluent. After treatment with each copolymer, the 3% pulp slurry was drained at 25 second intervals and compared to untreated pulp.

More specifically, copolymers 15-19 were evaluated and identified as follows:

copolymer 15 is an EO/PO block copolymer commercially available from Vantage Performance Materials under the trade designation Lumulse 1061L.

Copolymer 16 is an acrylate-based emulsion copolymer having the general formula according to formula (III):

wherein x is about 1 and y is about 1.

Copolymer 17 is an EO/PO block copolymer having the general formula according to formula (I) above:

wherein each x is about 25 and y is about 8.

Copolymer 18 has the same characteristics as copolymer 2 described above.

Copolymer 19 is an EO/PO block copolymer having the general formula according to formula (I) above:

wherein each x is about 20 and y is about 35.

The data show that the amount of effluent removed was significantly greater for the treated samples, as shown in fig. 8. The use of the EO/PO block copolymers of the present disclosure increases the drainage rate by about 30% to about 40%, while the use of the ethyl methacrylate copolymers of the present disclosure provides an increase of about 40%. This is important because it introduces a new functional chemical (i.e. anionically charged acrylate polymer in alkaline medium) that performs well in this application and has favorable regulatory approval (FDA indirect food contact).

The pulp was also compared to the cleanliness after a 25 second drainage interval. As shown in fig. 9, the faster draining pulp contained less dirty effluent and showed significant chemical oxidant demand (calculated COD) and total organic carbon (calculated TOC) reduction.

Example 6:

unbleached southern hardwood kraft pulp brown stock was collected before bleaching at 1% solids (before thickening to > 10%). After treatment with each copolymer at 3lb actives of each copolymer per metric ton of pulp, the 3% slurry was drained for 25 seconds and compared to untreated pulp. More specifically, copolymers 15-19 were again evaluated. The data show that the EO/PO block copolymer increased the water filtration rate in this application by about 70% to about 75%, as shown in fig. 10.

Example 7:

bleached southern hardwood kraft pulp was collected from the alkaline extraction stage with filtrate. After treatment with 3lb of EO/PO block copolymer per metric ton, the 3% pulp was drained at 25 second intervals and compared to untreated pulp. More specifically, copolymer 20 was evaluated. Copolymer 20 has the same characteristics as copolymer 19. The mass of the filtrate was removed and measured, and each experiment was repeated 3 times with blanks and treatments to demonstrate reproducibility. The data shows that a large amount of effluent was removed from the treated pulp, representing an increase in drainage of about 48%, as shown in fig. 11.

Summary of the relevant data:

the data indicate that the pulp mixture and process increases the rate at which the pulp can be drained in a washing operation. This may result in cleaner pulp at fixed time intervals, or higher pulp output (increased productivity). A balance of these two benefits can also be achieved.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims.

Claims

1. A pulp mixture comprising:

a lignocellulosic material;

water;

lignin;

an inorganic salt; and

a copolymer comprising two or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof;

wherein the copolymer is free of structural units containing silicone, and

wherein the lignin is present in an amount greater than about 150ppm based on the total weight of the pulp mixture.

2. The pulp mixture of claim 1, wherein the copolymer comprises ethylene oxide units and propylene oxide units.

3. The pulp mixture of claim 2, wherein the copolymer is a linear copolymer.

4. The pulp mixture of claim 2, wherein the copolymer is a branched copolymer.

5. The pulp mixture of any of claims 1 to 3, wherein the copolymer has a structure according to formula (I),

wherein:

x and y independently of each other have a value of from about 1 to about 200; and is

The ratio of x to y is from about 10: 1 to about 1: 10.

6. The pulp mixture of claim 5, wherein each x is from about 10 to about 30 and y is from about 20 to about 40.

7. The pulp mixture of claim 1, wherein the copolymer has a core and two or more chains extending from the core, wherein the core is derived from a hydroxyl-containing compound, and each of the two or more chains independently comprises ethylene oxide units and propylene oxide units.

8. The pulp mixture of claim 7, wherein the hydroxyl containing compound is selected from the group consisting of sorbitan, glycerol, erythritol, and combinations thereof.

9. The pulp mixture of claim 8, wherein the copolymer has a structure according to formula (II),

wherein:

a. b, c, d, w, x, y and z independently of one another have a value of from about 1 to about 200; and is

The w: a ratio, x: b ratio, y: c ratio, and z: d ratio are each independently from one another about 10: 1 to about 1: 10.

10. The pulp mixture of claim 9, wherein a, b, c, and d are each independently from about 7 to about 70, and w, x, y, and z are each independently from about 5 to about 50.

11. The pulp mixture of claim 1, wherein the copolymer comprises (meth) acrylic acid units and ethyl acrylate units.

12. The pulp mixture of claim 11, wherein the copolymer has a structure according to formula (III),

wherein:

The ratio of x to y is from about 10: 1 to about 1: 10.

13. The pulp blend of any of claims 1 to 12, wherein the copolymer is present in an amount of from about 0.10 to about 3.0 pounds of active per U.S. ton of oven dried pulp.

14. The pulp mixture of any of claims 1 to 13, exhibiting at least about a 5% increase in drainage rate from a pulp mat in the presence of the copolymer as compared to the drainage of water from a pulp mat in the absence of the copolymer.

15. The pulp mixture of any of claims 1 to 13, exhibiting an increase in dewatering rate, defined as the amount of water passing through a pulp mat per unit wash time in the presence of the copolymer, of at least about 5% as compared to the amount of water passing through a pulp mat per unit wash time in the absence of the copolymer.

16. The pulp mixture of any of claims 1 to 13, exhibiting a reduction in the amount of inorganic salts, measured after filtration of water from a pulp mat, of at least 5% in the presence of the copolymer compared to filtration of water from a pulp mat in the absence of the copolymer.

17. The pulp mixture of any of claims 1 to 16, wherein the lignocellulosic material is present in an amount of about 0.5 to about 20 wt% based on the total weight of the pulp mixture, the water is present in an amount of at least about 75 wt% based on the total weight of the pulp mixture, the inorganic salt is present in an amount of less than about 6 wt% based on the total weight of the pulp mixture, and the copolymer is present in an amount of about 0.10 to about 1.0 pounds of active per metric ton of oven dried pulp.

18. A method of improving drainage during pulp washing, the method comprising:

providing a pulp mixture comprising lignocellulosic material, water, lignin, inorganic salts, and a copolymer comprising two or more structural units selected from the group consisting of ethylene oxide units, propylene oxide units, (meth) acrylic acid units, ethyl acrylate units, and combinations thereof, wherein the copolymer is free of silicone-containing structural units, and the lignin is present in an amount greater than about 150ppm based on the total weight of the pulp mixture;

forming a pulp mat from the pulp mixture; and

filtering water from the pulp mat;

wherein the pulp mixture exhibits at least about a 5% increase in drainage rate from the pulp mat in the presence of the copolymer as compared to the drainage of water from the pulp mat in the absence of the copolymer.

19. The method of claim 18, wherein the step of filtering out water is performed in a brown stock washing process, a bleaching plant process, a commercial pulper process, or a combination thereof.

20. The method of any one of claims 18 or 19, wherein the copolymer has one of the following structures according to formula (I), (II), or (III),

wherein formula (I) is:

wherein:

The ratio of x to y is from about 10: 1 to about 1: 10,

wherein the formula (II) is:

wherein:

The w: a ratio, the x: b ratio, the y: c ratio, and the z: d ratio are each, independently of one another, from about 10: 1 to about 1: 10, and

wherein formula (III) is:

wherein:

The ratio of x to y is from about 10: 1 to about 1: 10.